1. Field of the Invention
The present invention generally relates to printer maintenance and reliability and more particularly to reducing electro-photographic printer maintenance and improving electro-photographic printer reliability.
2. Background Description
Purchasing a state of the art electro-photographic printer may require a major investment from a business concern. To recoup that investment, the business concern may keep the electro-photographic printer running 24 hours a day, seven days a week. So, any time that the electro-photographic printer is not operating normally, the owner is losing money.
From time to time electro-photographic printers experience toner/developer handling mechanism failures. While some small level of toner is always present, e.g., passing through fine internal filters, these failures frequently allow significant toner to escape into the local environment, e.g., a printer room. While generally, developer does not escape from the printer as airborne particulates, it may spill or leak into the printer and surrounding areas. This fugitive toner/developer can contaminate the printer room and expose operators there to unhealthy levels of toner/developer particles. Cleanup from these fugitive toner/developer misadventures often requires large amounts of both time (i.e., down time) and labor. So in some cases, expensive external air filtration systems are installed, sometimes directly attached to the printer, to capture fugitive toner before it causes much damage. Thus, the expense dealing with fugitive toner particles and/or developer may be significant.
Although toner itself is expensive, fugitive toner itself does not usually damage the printer. However, fugitive toner in the paper path, for example, adheres to the paper as it traverses the path to degrade the print results. Fugitive toner also contaminates the printer optics and coronas, all of which makes print jobs look dirty at best and unreadable at worst and in either event unusable. This down-time may be further exacerbated by printer damage from developer contamination. Moreover, the presence of fugitive toner tends to shorten the life of cleaner brushes and filters, which shortens the maintenance cycle, adding to maintenance costs. So, much of the fugitive toner/developer particle contamination must also be cleaned from the printer itself as soon as it is detected. Usually, excessive dusting is an early warning of a problem, such as the failure of a seal or a toner charging problem, that warrants a service call.
Furthermore, in addition to print head optics being contaminated from fugitive toner and/or developer, contaminants that also originate external to the printer may also cause problems. Again with print head optics contaminated or dirty, regardless of the contaminant, the print results may be unusable as well and certainly do not look unprofessional.
Thus, there is a need to detect the occurrence of contaminants in state of the art printers and especially, fugitive emissions of toner/developer immediately, prior to their further escape into the printing environment.